The present invention relates to a turbopump system for driving a plurality of pumps. The system finds particular application in the driving of a pair of centrifugal pumps to pump two separate propellant fluids into a rocket engine combustion chamber.
Many technical applications require the simultaneous pumping of two separate fluids, such as a rocket engine wherein the liquid fuel and oxidizer must be fed into a combustion chamber. Typically, these applications require matching the capacities and the speeds of the two pumps to the type of fluid which is being pumped and to the required pressure increase in order to achieve optimal efficiency of the two fluid pumping system while maintaining a minimal weight. It has been suggested to size the pumps so that they may be driven at the same speed using a single turbine as a power source. In this system, the pumps and the turbine rotor are rigidly linked by a single shaft. This design does not enhance the overall efficiency of the system, since the operating efficiency of each component (the two pumps or the turbine) cannot be optimized by using a single speed.
While it is possible to drive the two pumps at different speeds using a single turbine by interposing a speed reducer between the turbine and one of the pumps, this increases the weight and bulk of the system, as well as increasing the vibration of the system. Obviously, each of the pumps may be separately driven by its own turbine. Equally obviously, this design increases the weight and bulk of the system and is, therefore, undesirable.